Brake for forming metal plate and sheet



July 17, 1962 P. L. CADY, JR

' BRAKE FOR FORMING METAL PLATE AND SHEET Filed Feb. 15, 1960 7 Sheets-Sheet 1 INVENTOR.

ATTORNEYS.

July 17, 1962 P. L. CADY, JR

BRAKE FOR FORMING METAL PLATE AND SHEET 7 Sheets-Sheet 2 Filed Feb. 15, 1960 July 17, 1962 P. L. CADY, JR

BRAKE FOR FORMING METAL PLATE AND SHEET 7 Sheets-Shet 3 Filed Feb. 15, 1960 INVENTOR. Yercr L. Cad J1.

A TTORNE'YS July 17, 1962 P. L. CADY, JR

BRAKE FOR FORMING METAL PLATE AND SHEET 7 Sheets-Sheet 4 Filed Feb. 15, 1960 I INVENTOR. PerQB L. CacI .,J1'. BY 6 W M1 ATTORNEYS.

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July 17, 1962 P. L. CADY, JR

BRAKE FOR FORMING METAL PLATE AND SHEET '7 Sheets-Sheet 5 Filed Feb. 15, 1960 9m wm.

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ATTOFJVNS.

July 17, 1962 P. L. CADY, JR

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BRAKE FOR FORMING METAL PLATE AND SHEET Filed Feb. 15, 1960 '7 Sheets-Sheet 7 INVENTOR. Petgg L. Ca 1 31'. BY MWX ATTORNEYS.

3,044,526 BRAKE FGR FOmfiNG METAL PLATE AND SHEET Percy L. Cady, Ira, Darien Center, N.Y.

Filed Feb. 15, 1960, 591. N0. 8,603 17 Ciairns. (Cl. 153-16) This invention relates to a brake for forming metal plate and sheet and more particularly to a brake having a pair of cooperating aprons or wings which are severally adjustable with reference to a common mandrel and with reference to each other so that forms can be produced which present brakes are incapable of producing.

This application is a continuation in part of my copending application, Serial No. 641,352, filed February 20, 1957, for Sheet Metal Brake and now abandoned.

A principal object of the present invention is to provide a brake, the pivoted aprons or Wings of which are adjustable with reference to a common mandrel and with reference to each other so that the metal plate and sheet can be bent to forms which other present brakes are incapable of producing.

Another object is to provide such a brake which can be adjusted to operate on sheet or plate of any thickness up to the maximum for which the brake is designed, or with mandrels of different size and form.

Another object is to pro-vide such a brake in which the aprons or wings are either simultaneously or independently adjustable with reference to the forming axis to produce a particular form, the forming axis, as referred to herein, being the axis about which the workpiece is formed.

Another aim is to provide such an adjustment for selectively adjusting the aprons or wings either-independently or as a pair which is extremely simple and rugged in construction and which at the same time permits of a very fine adjustment.

Another object is to provide such a brake in which the aprons or wings are power actuated and in which the power piston cylinders are at all times arranged close to the sides of the frame and operate with a horizontal movement less than that of the aprons or wings so that the power drive for the aprons or wings does not increase the floor space required for the brake and does not provide an occupational hazard.

Another aim is to provide such a brake which can readily be set to semi automatic operation to facilitate the successive production of identical forms.

Another object is to provide a simple and powerful power actuated mechanism for moving the clamping ram and its mandrel to and from working position and which also includes a simple and effective means for manually adjusting the working position of the mandrel.

Another object is to provide such an adjustment for the working position of the clamping ram and mandrel whereby differential adjustment of the opposite ends of the clamping mandrel can be effected. v

Another object is to provide a simple gage stop against which the metal being formed is placed and which compensates for the subsequent stretch of the plate or sheet being formed.

Another object is to provide a simple and reliable calibrated coarse and fine gages by which the exact position of the aprons with reference to the forming axis can be readily and directly determined.

Another object is to provide such a brake which, while capable of being set to fine adjustment, is simple, rugged and inexpensive and will stand up under conditions of severe and constant use without getting out of order or requiring repairs.

Other objects and advantages of the invention will be apparent from the following description and drawings in which:

States Patent 3,044,526 Patented July 17, 1962 FIG. 1 is a front elevational view of a brake for metal plate or sheet embodying the present invention. FIG. 2 is a top plan view thereof.

FIG. 3 is a fragmentary vertical sectional view, on an enlarged scale, taken generally on line 3-3,- FIG. 2.

FIG. 4 is a fragmentary horizontal section taken generally on line 44, FIG. 1.

FIG. 5 is a view similar to FIG. 1 but with parts broken away to illustrate operating mechanism contained within the end columns of the brake frame.

FIG. 6 is an end elevational view, viewed from the right-hand ends of FIGS. 1 and 5 FIG. 7 is an enlarged vertical fragmentary section taken generally on line 77, FIG. 5.

FIG. 8 is a fragmentary enlarged vertical section taken generally on line 8-8, FIG. 7.

FIG. 9 is a fragmentary enlarged vertical section taken generally on line 9-9, FIG. 5.

PEG. 10 is a fragmentary enlarged vertical section taken generally on line 1tl10, FIG. 5.

FIG. 11 is a fragmentary front elevational view of the right-hand end column of the brake, as viewed in FIGS. 1 and 5 with the cover 193 removed.

FIG. 12 is an enlarged fragmentary horizontal section taken generally on line 1212, FIG. 11.

FIG. 13 is a side elevational view of the treadle or foot switch used to operate the clamp.

FIG. 14 is a diagram of the hydraulic circuit and showing a very simplified diagram of the electrical component, limit switches and holding circuits in particular being eliminated for the purpose of clarity.

FIGS. 15 through 21 are diagrammatic representations illustrating a particular closed tubular piece capable of being made with the present brake from metal sheet or plate.

FIGS. 22 and 23 are similar views showing the manner in which a two ply workpiece, such as metal with a rubber lamina, can be flanged by the individual adjustment of the aprons forming the subject of the present invention.

FIGS. 24 and 25 are similar views showing the manner in which a workpiece can be made to form to two different radii by individual adjustment of the forming aprons in accordance with the present invention.

FIGS. 26 and 27 are similar views showing the manner in which a workpiece having two thicknesses, such as with a lamina-ted workpiece, can be formed with the present brake.

The frame of the sheet metal brake comprises a pair of end columns or stands indicated generally at 30 and connected at their lower ends by a horizontal beam 31 and at their upper ends by a horizontal beam 32. Each of the columns 30 has a rectangular base plate 33 Welded to and supporting a main or backbone plate 34 of the column. This main plate 34 of each column is reinforced along its front and rear vertical edges by flanges 35 and 36 so as to provide a post which is of channel form in cross section opening outwardly as best shown at the left of FIGS. 2, 4 and 5. In addition the main or backbone 34 of each column is reinforced by triangular gussets 38 the bottom edges of which are welded to the base plate 33. Each bottom plate 33 also has welded thereto an upstanding plate or bar 3f to which the ends of the lower bottom cross beam 31 are suitably secured in any suitable manner. This cross beam is preferably of channel form in cross section as best shown in FIG. 4.

Each column 39 also includes an upper box portion indicated generally at 40, these box portions being secured to the upper parts of the main or backlbone plates 34 in opposing relation to each other. Each box portion 40 comprises a front plate 41 and a rear pi ate 42, these plates being secured, as by welding, to the front and rear edges, respectively, of the main plate 34 of each cylinder.

column. The outboard or opposing edges of these plates lateraldisplacement of these pins. Accordingly, vertical 41, 42 are connected by a cross plate 43 so as to complete the box section.

. The top of each box portion 40 is enclosed by a block 44 secured therein in any suitable manner and to which blocks the opposite ends of the upper cross beam 32 are secured, the latter preferably being of channel form in cross section with its flanges projecting downwardly. A horizontal cross plate 45 connects'the bottom edges of the 'front and rear plates 41, 42 of each box portion 40, the plates 43 projecting downwardly below these horizontal cross plates. The depending end of each of these plates 43 carries a boss 46, these bosses being 'inhorizontal coaxial relation with each other and with bosses 48 on the main plate 34 of each column 46. The bosses 46, 48 of each column 30 carry the main pivot pin 49 of the brake, each main pivot pin also being supported at its center in a plate 50 depending from the center of the corresponding horizontal cross plate 45 as best shown in FIG. 5.

The main pivot pins 49 support the knuckles of front and rear aprons indicated generally at 51a and 51 as hereinafter described, these aprons cooperating with a clamping ram indicated generally at 53, in bending a plate or sheet of metal 55 to the desired form. This clamping ram 53 includes a holder in the form of a vertical plate or beam 54 arranged directly above and parallel with the axis of the main pivot pins .49 and having its opposite ends protruding through openings 56 in the plates 43 into the interiors of the box portions 40 of the end columns 30 of the brake frame.

Within each column 30 of he brake frame, the corresponding end of the plate or beam 54 is guided for vertical movement toward and from the axis of the main pivot pins 49 between a pair of slide guides 58 on the opposing faces of the front and rear plates 41, 42 of each end column 30 of the brake frame, 'as best shown in FIGS. and 7, brass slides or liners 59 being interposed'between these slide guides 58 and the plate or beam 54. The plate or beam 54 is held against endwise displacernent by having a brass liner 61) secured to each of its ends and engaging a slide guide 61 secured to the main or backbone plate 34 of the corresponding end column as best shown in FIG. 5.

Hydrau-lically or pneumatically actuated means are provided for moving the opposite ends of the clamping ram.

53 vertically into and out of, engagement with the workpiece on the two aprons 51, 51a, these means preferably being constructed as follows: 7

The numeral 65 represents an ear secured to and projecting from the exterior face of the main plate 34 of each end column 30. To each of these ears is pivoted the lower end of a cylinder 66 containing a piston 68 including a piston rod projecting upwardly from the piston rod 68 and this block 69 is interposed between the generally horizontally projecting arms 70 of a corresponding pair of bell crank lever-s 71, the other general=ly vertically projecting arms of which are indicated at 72. The arms 72 of the bell crank levers 71 are housed within the box portions 40 of the end columns 30 of the frame and the arms 70 project outwardly through openings 74 in the main or backbone plates 34 of these 'col-v umns. The outer ends of the arms70 are connected to the blocks 69 by pivot pins 75 and within the box portions 40 the bell crank levers 71 are supported at their centers by large pivot pins 76. Each pivot pin 76, as best shown in FIG. 7, is journalledin a bearing 78 in the stem 79 of a screw 80, the bell crank levers 71 being A block 69 is fixed to the upper end of each i movement of the-horizontally projecting arms 70 of the bell crank levers by the piston 68 effect horizontal movement of the arms 72 thereof, these last arms forming one side of a toggle linkage connecting with the corresponding end of the plate or beam 54 of the clamping ram 53. For this purpose, the lower ends of the arms 72 of each pair of bell crank levers 71 embrace the upper end of a toggle link 84 and are connected thereto by a pivot pin 85. The lower end of the toggle link 84 is interposed between a pair of cars 86 to which it is connected by a pivot pin 88. Each pair of cars 86 is fixed to and projects upwardly from the corresponding end of the plate or beam 54 of the clam-ping ram 53.

Means are provided for adjusting the working position of the clamping ram 53, these means being preferably constructed as follows:

The numeral 90 represents a hand crank suitably journalled on the column 30 at one end of the brake and turning a pinion 91 connected by a drive chain 92 with a pinion 93 at one end of an adjusting shaft 94 suitably journalled on the upper end of that columns. One end of this shaft 94 is connected by a releasable coupling or jaw clutch 95 with a shaft 96, the opposite end of which is suitably journalled at the end column 30 of the machine The coupling 95 can be manually connected or disconnected by the manipulation of a hand lever 98, the latter being shown as being pivoted, as indicated at 99, to one end a bracket to swing about a horizontal axis. The end of the hand lever 98 opposite its grip is shown as being bifurcated and as embracing a sliding coupling member 101m which it is connected by means of opposing pins 102 in an annular groove 103 provided in the coupling member 101. This coupling member 101 is compelled to turn with the shaft 94 by means of a key 104 and has jaws 165 arranged to mesh with face jaws 1116 on a coupling member 108 fixed to the shaft 96.

Above each end column 30, the corresponding shaft 94 and96 carries a Worm 110 which is fixed thereto and which meshes with a worm wheel 111. The latter is suitably secured, as by the screw 112 and pin 113 shown in FIG. 7, to the upper end of a nut 114 journalled to rotate about a vertical axis in a bearing 115 in the block 44 at the upper end of each column 30. Each nut is threadedly secured to the upper threaded end of the corresponding screw 80 and is held against axial displacement with reference'to its block 44 by a thrust washer 116 and by a retaining ring 118, the latter being held to the block 44 by a retaining ring or collar 117.

The workpiece is engaged by a mandrel 121 removably secured to the bottom of the plate or beam 54 of the clamping ram 5-3. In the form of the invention illustrated in FIGS. 1-21, the mandrel is shown as being in the form of a rectangular blade having a rounding bottom longitudinal nose portion 121 engaging the workpiece. The upper edge of this blade is shown as clamped in a rabbet 122 along the lower edge of the beam or plate 54 of the clamping ram 53 by means of a plurality of clamping plates 12 3 clamped against the upper end of the blade 120 by means of a plurality of screws 124. It will be seen that in deforming a workpiece held down on the aprons 51 by the mandrel blade 120, it is important that the forming pressures be balanced so as not to displace its nose 121 laterally.

' various construction but is shown as an example as conarranged on opposite sides of. the shank of the screw. 7

Eachpin 76 extendsthrough a vertical slot 81 in the front and rear plates 41,,42'of the corresponding end column 30 and through guide slots 82 in plates 83 welded to the exterior faces of these plates 41, 42. These slots 81, '82 penrnit vertical adjustment of the pins 76 ashereinafter described, and at the same time prevent horizontal structed as follows:

Each apron 51, 51a includes a wing in the form of a large metal plate extending lengthwise of the mandrel 120 and at the start the forming operation these wings or plates are arranged is closely spaced vertical face-to-face relation, as shown in FIG. 9, on opposite sides of a plane intersecting the forming axis of the mandrel 120 which in the form shown in FIGS. 1-21 is at the center of its,

rounding nose 121. Both wings 1-25 have ends of reduced height and the wing at the front of the brake is designated at 125 and the wing at the rear of the brake is designated at 125a, the latter being somewhat longer than the former. Along the upper edge of each wing 125, 125a, a reinforcing angle bar 126 is secured as by screws 127,'to its outer face, these angle bars extending the full length of the wings and each clamping a forming blade 128 to the top of each wing. For this purpose, each forming blade 128 is L-shaped in cross section and is clamped in a rabbet 129 along the upper edge of each wing. The Working surfaces of these forming blades 128 face upwardly.

Each apron 5-1, 51a is independently pivoted on the main pivot pins 49 and are also independently adjustable toward and from the forming axis by means whichare preferably constructed as follows:

The numeral 130 represents a square nut secured, as by screws 135, FIG. 9, to each end of each wing or plate 125, 125a on the outer face thereof, these nuts being arranged parallel with one another and in planes perpendicular to the forming axis. A screw 138 Works in each nut 130, these screws being rotatably mounted on pins 139, the inner threaded end of 140 each of which pins is screwed into a hinge arm 141 having a pair of knuckles 142 journalled on the corresponding main pivot pin 49 as best shown in FIG. 5. As shown in this figure, the knuckles 142 of the rear apron 51a are arranged in a1- ternation to the knuckles 142 of the front apron 51.

Each screw 13 8 is pinned, as indicated at 144, to a worm wheel 145, these worm wheels being arranged in a common horizontal plane in the upright position of the aprons 51, 51a. To prevent lengthwise movement of each screw 138 and its worm :wheel 145 lengthwise of the corresponding pin 139, a collar 146 ispinned to the outboard end of each pm 139 to engage the corresponding worm wheel 145. The opposite end of each screw 138 rotatably engages the corresponding hinge body 141 and preferably has an enlarged annular flange 148 interposed between this hinge body 141 and its nut 130 and bearing a series of graduations 149' so that the angular position of each screw 138 can be determined by reference to the scale provided by these g'raduations 149. This scale provides a fine adjustment scale for the position of each screw 138, thereby to determine, with a high degree of accuracy, the axial position of each nut .130. A coarse scale for the position of each apron is provided by a bar 150 secured to each nut 130- to project upwardly therefrom and bearing a series of graduations 151 arranged to traverse a reference point (not shown) on the corresponding hinge body 141.

As previously indicated, the Worm wheels 145- are adapted to be brought to a common horizontal plane and when brought to this position, each engages a worm 155 fast to an adjusting shaft 156. This adjusting shaft extends the full length of the brake and is journalled in bearings 158, 159 on the end columns '30 of the frame. This shaft has fixed thereto a sprocket 160 connected by a chain 161 with a sprocket 162 fast to the crankshaft 163 of a hand crank 164. It will be seen that turning the hand crank 164 turns the shaft 156 and its worms 155, thereby to turn the worm wheels 145 engaging these worms and hence the corresponding screws 138.

Means are provided for swinging the aprons 51, 51a independently of each other on the main pivot pins 49, these means being preferably constructed as follows:

The numeral 165 representsan car fast to and projecting outwardly from each nut 13%. To each ear is pivotally connected, as indicated at 166, the piston 168' contained in a cylinder 169. The piston and cylinder for the front apron are distinguished by the suffix a. The outer end of this piston is pivotally connected, as indicated at 170, to an car 171 fixed to and projecting outwardly from the corresponding plate 41, 42 of each end column 30.

An adjustable stop is provided for initially positioning forwardly projecting bars 176 which are spaced to provide a way 178 Slidable in each way 178 is a block 179 which can be fixed at any location along the way by tightening a screw 180. The block 179 carries a tube 18 1 opening toward the mandrel and closed at its other end by a plug 182. A stop in the form of a plunger 183 is arranged in this tube 181 and is biased toward the mandrel 120 by a spring 184 interposed between it and the 'plug 182. Each plunger 183 also carries a horizontal plate 185- on which the edge of the plate or sheet workpiece to be bent rests. The function of the spring loaded stop 183 is to position accurately the edge of the plate or sheet to be formed but to give during the actual forming operation to compensate for the elongation of the sheet or plate which occurs as a part of its being formed.

For repeated operation of the brake in the production of identical forms, it is desirable that each apron 51,51a be individually stopped at the angular position required so that the operator has merely to' place the workpiece against the stops 183, clamp the workpiece against the aprons 51, 51a and by the mandrel 121}, and start the operation of these aprons, the aprons automatically stopping when the workpiece is bent to the required form. The mechanism for accomplishing this is preferably constructed as follows:

The numeral represents a segmental plate fast to the exterior of one knuckle 142 of each apron 51, 51a, this being at the right hand end of the brake as viewed in FIGS. 1, 2 and 5. As best shown in FIG. 10, a Wire 191 is fixed to the leading edge of each of these segments so that as eachapron '51 or 510 is swung about the main pivot pins 49, the corresponding wire 191 is moved longitudinally proportionally. Each wire 191 passes, around pulleys 192 (FIGS. 1 and 2) to the top of the adjacent column 30 of the frame and thence downward along the rear side of this column behind a cover plate 193. The other end of each wire 191, as best shown in FIG. 11, is secured to a vertically reciprocating rod 194, these rods being mounted for this purpose in stationary slide bearings 195. Weights 196 are secured to thhe lower ends of the rods 194 and a sleeve 198 is adjustable along each of these rods. The upper end of each sleeve is in the form of a square head 199 carrying a set screw 209 having a handle by means of which the set screw can be released to free the corresponding sleeve 198 for adjustment vertically along its rod 194, the sleeves being guided in stationary slide bearings 202. Each set screw 20$) extends through a vertical slot 203- in the cover 193 for ready accessibility of its handle and the cover 193 is also provided between these slots with another vertical slot 204 through which a graduated scale 256 is visible. This scale is calibrated in degrees of angularity up to 90 and is traversed by a pointer 258 on the square head 1-99 of each of the sleeves 198.

Each of these sleeves 198 also carries a stop in the form of a cam 259 operating an electrical switch, the switch for the front apron being designated at 210. and the switch for the rear apron being designated at 210a.

Referring to the hydraulic circuit, FIG. 14, the numeral 215 designates a motor driving a pair of hydraulic pumps 216 and 218 drawing oil from a supply 219. The pumps 216, 218 deliver the oil through lines 225 and 221, respectively, to a common line 222 delivering the oil to a three position spring centered solenoid valve 223. The lines 225 and 221 contain check valves- 224 and 225, respectively, opening in the direction of oil flow from the pumps and the line 220 contains a relief valve 226 returning oil under excess pressure to drain 228. The

7 common line 222 contains a relief valve 229 returning oil under excess pressure to drain 228.

In the centered position of the three position valve 223 the supply line 222 connects with a port 230 providmg communication with a line 231 having a branch 232 leading to a solenoid valve 233. In the deenergized condition of this solenoid valve, the line 232 is connected by port 234 to drain 228. In the energized condition of this solenoid valve the flow of oil from the line 232 to drain is cut oif, this line being provided with a relief valve 235 discharging to drain 228 under excess pressure.

The spring centered three position solenoid valve 223 is moved to one extreme position to move the clamping ram 53 into engagement with thhe workpiece by energizing its solenoid 236. This can be done by a foot switch 237 actuated through a foot treadle 24-8, FIG. 13, by the operator. When the solenoid 236 is so energized, the oil supply line 222 is connected by port 238 toa line 239 connected by flexible hoses 246 to the lower ends of the clamping cylinders 66. The line 239 contains a relief valve 241 discharging to drain 228. Also when the solenoid 236 is so energized, port 242 connects the line 231 with a line 243 connected by flexible hoses 244 with the tops of the upper ends of the clamp cylinders 66 to permit the escape of oil therefrom.

The spring centered three position solenoid valve 223 is moved to its other extreme position to move the clamping ram 53 out of engagement with the workpiece by energizing its solenoid 245. This can be done by a foot switch 246 actuated by the operator, it being preferable to actuate the foot switches 237 and 246 in alternation by means of the foot treadle 248 shown in FIG. 13. When this solenoid 245 is so energized, the oil supply line 222 is connected by port 249 to the line 243 and the line 239 is connected by port 259 to the line 231.

The pistons 169 of the two aprons 51, 51a are selectively actuated by oil supplied from the line 231 by substantially identical hydraulic and electrical circuits, and hence a description of one will be deemed to apply to both the components of the hydraulic and electrical circuit for the front apron being distinguished by the suflix a. Each of these hydraulic circuits is preferably constructed as follows:

The numeral 255 represents a branch line containing a check valve 256 and leading to a three position spring centered solenoid valve indicated generally at 253. In the spring centered position of this solenoid valve, all lines connected with the valve are blocked as shown.

Each spring centered three position solenoid valve 253 is moved to one extreme position to effect operative movement of the apron 51 by energizing its solenoid 259. This can be done by means of a switch 260, the two solenoids 259, 2590: also preferably being in series with the solenoid 261 of the valve 233 by means of a branched electrical line 262 so that energization of either solenoid 259 or 259a will also effect energization of the solenoid 261 of the valve 233. When the solenoid 259 is so ener-' gized, oil from the branch line 255 is conducted by port 263 to a line 264 connected by flexible hoses 265 with the bottoms of the cylinders 169. Each line 264 contains a check valve 276 opening toward the cylinders 169. Also when the solenoid 259 is so energized, a port 271 connects the line 272 from the top of the cylinders 169 with drain 228. The line 272 is connected to the top of the pair of cylinders 169' by flexible hoses 273.

Each spring centered three position solenoid valve 258 is moved to its opposite extreme position to eifect return movement of the aprons 51 by energizing its solenoid 274. This can be done by the switch 219 which also simultaneously energizes the solenoid 261 of the valve 233 through a line 275. When solenoid 274 is so energized branch line 255 is connected by port 276 with line 272. A regenerative circuit line 267 connects the line 264, between the cylinders 169 and check valve 278*, with the line 255, between the three position solenoid valve 258 and the check valve 256.

A globe valve 278 is provided between lines 264 and 272 to permit slow movement for setting up the aprons. Likewise a globe valve 279 can be provided between lines 239 and 243 to permit slow movement for setting up the clamping ram 253.

A feature of the brake resides, in addition to the independent movement of the aprons 51, 51a, in the specific adjustability of 'these aprons with reference to the forming axis to produce from plate or sheet metal of different thickness the shapes shown in FIGS. 15 to 27. FIGS. 15 to 21 illustrates forming a somewhat complicated closed tubular shape which can be done with plate or sheet metal of different thickness only because of this adjustability of these aprons. In the production of this form the round nosed mandrel 12b is used. FIGS. 22 and 23 illustrate the manner 12%} is used. FTGS. 22 ply thickness can be made on a body of two ply material with the differential adjustment of the aprons in accordance with the present invention. In the production of this form a sharp edged mandrel 286 is used. FIGS; 24 and 25 illustrate the production of a plate or sheet of metal to produce a double radius bend, the mandrel 281 having one part 282 conforming to the smaller radius and having another part 283 conforming to the larger radius. FIGS. 26 and 27 illustrate the formation of a metal plate having different thicknesses. The mandrel 284 is shown as having a cylindrical nose 255.

Operation in this description of the operation of the brake, it will be assumed that a metal plate is to be formed into the closed tube around the rounding nose 121 of the mandrel 12s as illustrated in F163. 15-21. It will also be assumed that the motor 215 is running and driving the pump 216 and 218.

in producing the closed tube shown in FiG. 21 from the plate 55, the forming axis is the center of the rounding nose of the mandrel 12d and this forming axis must be coincident with the axis of the main pivot pins 49 on which the aprons 51, 51a swing. In the event that it is necessary to raise or lower this forming axis to effect such coincidence, as in changing from the mandrel shown in FIGS. 1-21 to. the mandrel shown in FIGS. 22 and 23, for example, the height of the mandrel is adjusted by turning the crank 9%, FIGS. 5 and 6, through the chain 92-, turning the sprocket 93 fast to the adjusting shaft 94. Assuming that it is desired to adjust both ends of the mandrel 129 uniformly, the coupling 95, FIGS. 2 and 3, would remain coupled during this adjustment so that the shaft 26 turns with the adjusting shaft 94, thereby to turn both worms 116 at the same rate. Accordingly both Worm wheels 111 are turned in unison, thereby, FIG. 7, :to turn the nuts 114 and raise or lower the screws 50, this being permitted by the vertical frame slots 81, $2 for the pins 76 which hold the screws 86 against turning, this pin and slot arrangement also serving to center the anchored upper end of each toggle for bringing the mandrel into and out of clamping operation as hereinafter described. Vertical movement of these screws ill effects vertical movement of each of these toggles 72, 84 and the clamping plate or beam 54together with the mandrel 12% suspended therefrom.

If it is desired to adjust one end of the mandrel higher than the other, or to correct any such differential, the left hand end of this mandrel, as viewed in FIGS. 1, 2 and S is adjusted to the proper height as above described, the shift lever $8, FIG. 2, is moved to uncouple the clutch or coupling 95, FIG. 3, and the crank 90, FIGS. 1, 5 and 6 is then turned in the proper direction, this turning only the adjusting shaft 94, FIG. 2, thereby to turn the worm wheel 111 at the right hand end of the brake, as viewed in FIGS. 1, 2 and 5, to the exclusion of the worm wheel 111 at the other end of the brake. Accordingly, only the nut and screw adjustment 114, 88 at this right hand end of the brake will be actuated and hence only the corresponding end of the mandrel 120 will be raised or lowered.

An important feature of the invention resides in the adjustability of the working surfaces or forming blades 128 of the aprons 51, 51:: with reference tothe forming axis, which, as above described is coincident with the axis of the main pins 49 for these aprons. Assuming it is desirable to adjust both aprons 51, 51a uniformly in this regard, this adjustment is eifected by turning the crank 164, FIGS. 1, and 6, thus, through the chain 161 turningthe sprocket 160 fast to the shaft 156 carrying the worms 155. These worms, in the pendent position of the agrons 51, 51a, engage the worm 'Wheels 14-5, FIGS. 4' and 9, so as to turn these worm wheels and the screws 138 pinned thereto. Each screw 138 is rotatably secured, but held against longitudinal movement with reference to, the knuckle 141 at each end of each apron and hence this rotation of these screws 13% serves to move the sleeve nuts 13!) longitudinally. Since these sleeve nuts are secured by the screws 135, FIG. 9, to the wings or plates 125, 1250 of the aprons 51, 51a, this adjusts these wings or plates the forming blades 128 carried thereby, with reference to the forming axis. The coarse adjustment of each apron 51 or 51a can be-seen at each end of the scale on the upstanding rod 150 on each sleeve nut 130 and the fine adjustment of each apron can be seen on the scale 149 around the top of each sleeve nut 130.

After having correctly adjusted, say, the apron 51, if it should be desired to adjust the other apron 51a to a different radius with reference to the forming axis, the

apron 51 is swung out or raised (as hereinafter described) so as to free its worm wheels 145 from the worms 1441 Accordingly, further turning of the crank 364' and the shaft 156 carrying the worms 155 serves only to turn the worm wheels 145 of the apron 51a so that only the wing 125a and forming blades 1% of this apron 51:: will be adjusted toward and from the forming axis. This differential adjustment of the aprons 5 1, 51a is required to produce the forms shown in FIGS. 22-27.

After such adjustment and with the clamping plate or beam 54 and its mandrel 129 in elevated position, the workpiece 55 is placed upon the aprons 51, 51a from the front of thebrake and its rear edge is brought against the spring backed stop pins 183, PEG. 9, and is supported on' the plates 1S5 carried by these stop pins.

With the motor 215 and pumps 216, 218, FIG. 14, running oil at this time is being supplied under pressure from the source 219 through the lines 221 and 221 to the common line 222, this .oil passing through the port 230 of the now spring centered three position solenoid valve 223 tothe line 231 and thence through the port 234 of the deenergized solenoid valve 233 to drain 223'.

The operator first brings the clamping ram 53 down to cause the nose 121 of the mandrel 120 to clamp the workpiece 55 against the forming blades 128 of the aprons 51, 5-112. He does this by stepping on that side of the foot treadle 248, FIG. 13, which closes the electrical switch 237. This energizes the solenoid 236 so as to shift the spring centered solenoid valve 223 so as to connect its port 238 with the lines 222 and 239 and its port 242 with the lines 243 and 231. Accordingly, oil under pressure from line 2'22 flows through port 238 and line 239 into the bottoms of the cylinders 66 thereby to project the pistons 68. The oil at the opposite sides of these pistons 68 is relieved through the lines 24-3, port 242; line 231' and solenoid valve 2-33 to drain 228.

This projects the pistons 68 thereby to swing the bell crank levers 71 about the pivot pins 76. The end 72 of each of these bell crank levers form one side of a toggle linkage 72, 84 which forces the clamping ram 53 downwardly in response to this projection of the pistons and piston rods 68. In this movement the clamping ram 53 is guided against lateral displacement by slide guides 53 (FIG. 5) and against endwise displacement by the slide of the toggle linkage 72, 84 is stabilized by the pin 76,

FIG. 7, being held against horizontal displacement by the frame slots 81, 82' and against vertical displacement by the nut and screw 80, 79. This action of the pistons 63 is in the cylinders 66, through the bell cranks '71 and toggle links 72, 84, brings the forming axis of the mandrel 120 (center of its nose 121) into concentricity with the axis of the main pivot pins 49 and the nose 12-1 of the mandrel against the top of the workpiece 55 toclamp it down on the aprons 51, 51a. When the pressure supply to the spring centered solenoid valve reaches the setting i of the unloading valve 226, the output from pump 216 is unloaded through this unloading valveg226 to drain and the clamping pressure is determined by the setting of the unloading valve 239.

Since both the mandrel 120 and itssupporting beam or plate 54 are of relatively thin plate-like form, it is apparent that they would be subject to lateral distortion if unbalanced pressures were initially applied by the aprons 5 1, 51a. Accordingly, it is desirable that where possible, for approximately the first 15 degrees of the angular movement of each of these aprons in bending the Workpiece that they move at the same rate to impose equal and opposite lateral forces against the mandrel. It is important that these aprons be thereafter capable of independent manipulation, however, as will be seen from an inspection of FIGS. 15-2 1.

The apron 51 is swung outwardly and upwardly to deform the workpiece by closing the switch 260", FIG. 14. This energizes the solenoid 259 of the spring centered solenoid valve 258 so as to bring its port 263 between the lines 255 and 264 and so as to bring its port 271 between the line 272 and the drain 228. This also energizes the solenoid valve 233 so as to move its port 234 out of register with the line 232 and drain 228 and hence divert this last line to direct oil through the valve 258. Accordingly, oil under pressure from this branch line 255 of the oil supply line 231 flows through port 263 and line 264 to the bottoms of the cylinders 169 so as to retract their pistons 169 and piston rod 168. At the same time oil on the opposite sides of these pistons escapes through line 272 and port 271 to drain 228.

Again, when the pressure of this unloa ding valve 226 is reached the output of pump 216 is again unloaded through this valve to the drain 228 and the aprons are actuated by the pump 218.

For initial simultaneous operation of the two aprons 51, 51a, the operator, in addition to closing the electrical switch 260 also closes the switch 260a. This simultaneously actuates the apron 51a along with the apron 51. Thehydraulic and electrical circuit and components for the apron 5111' are exactly the same as for the apron 51 and hence the description. will not be repeated, the components for the system actuating the apron 51a being distinguished by the sufiix a functioning in the same manner. I

As illustrated in FIG. 15., the first step in forming the tubular part illustrated in FIG. 21 is to bring each oi the aprons 51, 51a up 45 to provide a flange 29%! along one edge of the workpiece. Producing this flange results in an elongation of the workpiece transversely of its bend, this being compensated for by the spring backed stop pin 183. To produce such 45f bends by bothaprons 51, 51a the pointers 20.8, FIG. 11, will have been each set to 45 on the 'sca1e206. This is done by loosening the set screws 200 for each sleeve 198 and moving each sleeve vertically until its pointer 298 is in register with 45 on the scale 206 following which the set screw 290 is retightenedl With such adjustment of the sleeves 193 with reference to the wires 19 1 which wind around the segments Nth FIG. 10, on the knucles of the two aprons 51, 51a, as these aprons reach their 45 position, as illustrated in FIG. 11, their wires 191 move their sleeves 1 l 198 to a position where their stops or cams 209 trip the two switches 210, 210a, FIGS. 11 and 14.

When this occurs the solenoids 274 and 274a are energized to connect the oil supply lines 255 and 2554 to the lines 272 and 272a, respectively, the closing of these electrical switches 210, 210a also energizing the solenoid 261 hf the solenoid valve 233. This establishes a regenerative circuit to permit the aprons 51, 51a. to return on the effective area of the piston rods 168, 1 68a. Thus, pressure so established on the inlet side of the solenoid valves 258, 258a is applied through ports 276, 276a and lines 272, 272a, respectively, to the full area sides of the pistons 169, 16951.. This oil is in part supplied from the piston rod sides of these pistons through the lines 264, 264a and 267, 267a. Holding circuits and limit switches (not shown) are of course provided to complete the return movement of the aprons 51, 51a and to demergize the solenoids 261, 274, 274a at the completion of the return movement of these aprons, a simplified electrical circuit being illustrated for clarity.

The operator then presses down the clamp return side of the foot treadle 248, FIG. 13, thereby to open the switch 237 and close the switch 246. Accordingly, the solenoid 245 is energized to connect the lines 222 and 243 through the port 249 and to connect the lines 239 and 231 through the port 250. Accordingly, oil under pressure flows from line 222 through port 249 and line 243 to the top side of the cylinders 66 to move the pistons 68 downwardly. The oil from the undersides of these pistons escapes through the line 239 port 250, line 231 and port 234 of solenoid valve 233 to drain 228.

This moves the outboard arms '70 of the bell crank levers 71 downwardly to lift the clamping ram 53 through the link 84. Accordingly, the mandrel 120 is lifted from the clamping engagement with the workpiece 54, a complete sequence of the operation of the brake having completed and the parts being returned to the position assumed at the start of the description of operation.

After the run has been completed, the stops 183 are reset, by loosening the screws 180, FIG. 9, and adjusting the blocks 179 also the arms 176 to properly position the spring backed stops 183 for the next operation illustrated in FIG. 16. This comprises providing a second flange 291 in the workpiece 55 at 90 degrees both to'the body of the workpiece and to the first flange 290. No resetting of the clamping ram or of the apron stop switches 210, 210a is required and the operation of the brake in providing this second flange 291 is exactly the same as in providing the first flange 290.

, In like manner a third 90 flange 292 is provided.

After the run of workpieces has been completed to this point, the pointers 208 are reset, FIGS. 11 and 12, by loosening the set screw 200 and moving the sleeves 198 along the rods 194 until the pointers 208 register with 77 /2 on the scale 206.

The workpiece 55 is then replaced in the brake and clamped by the mandrel 120 upon the aprons 51, 51a by closing the switch 237 as previously described. The switches 260, 260a are then closed to swing the aprons 51, 51a outwardly and upwardly, their movement being continued until they reach the 77V2 position illustrated in FIG. 18. Accordingly, a 155 bend 293 is provided in the workpiece. At this point the cams 209 on the sleeves 198 engage and close the two switches 210, 210a to start the return movement of the aprons 51, 51a. Following the return of the aprons, the operator closes the switch 246 to raise the clamping ram and release the workpiece.

The operator then sets the pointer 208 for the rear aprons 51a at 80 on the scale 206 and sets the pointer 208 for the front apron 51 at this being done by loosening the set screws 200, FIGS. 11 and 12, adjusting the sleeves 198 along the rods 194. The workpiece is then placed on the aprons, the mandrel 120 brought down to clamp it on the aprons 51, 51a and the switches 260 and 260a closed to swing the aprons 51, 51a outwardly and upwardly. When the apron 51 reaches the ten degree position shown in FIG. 19, its cam 209 closes its switch 210 and when the apron 51a reaches its position its cam 209 closes the switch 210a, suitable holding circuits (not shown) being provided to provide for the simultaneous return of the two aprons. Accordingly, the large flange 294 is provided in the workpiece and on return of the aprons, the mandrel is raised to release the workpiece.

Following this the workpiece is placed on the aprons 51, 51a and the clamping ram 53 and its mandrel 120 brought down to complete the bend 293 to a full 180 and to bring the flanges 290 and 294 into firm contact with each other. Since this is a straight pressing operation, either the clamping ram 53 can be adjusted for this operation by turning the crank 90, or the aprons 51, 51a can be adjusted by turning the crank 164.

Following this the pointer 208 for the rear apron 51a is set to 70 on the scale 206, FIGS. 11 and 12, and the pointer 209 for the front apron 51 is set to 20 on the scale 206, this being done by loosening the set screws 200 and adjusting the sleeves 198 along the rods 194. The workpiece is then placed with its flange 294 across the aprons 51, 51a and the mandrel 120' brought down to clamp the workpiece thereon. The aprons are then swung outwardly and upwardly to form a 90 flange 295 on the end of the flange 294 following which the cams 209 engage the switches 210, 210a to return the aprons. Upon raising the mandrel 120, the completed workpiece, as shown in FIG. 21 is removed.

As previously set forth, a feature of the invention resides in the ability to adjust the working surface of the two aprons 51, 51a diiferent distances from the forming axis and FIGS. 2227 illustrate the products which could not be produced except for this feature. As previously explained in detail, this differential adjustment is effected by holding one apron in an elevated position so that it is disengaged from its adjusting worms while turning the common Worm shaft (through crank 164) to adjust the working surface of the other apron with reference to the forming axis.

FIGS[ 22 and 23 illustrate the manner in which a flange 296 can be provided on a plate 298 the body of which has a ply 299 of some material such as rubber. To produce a sharp cornered flange, the mandrel 281 is sharp edged and this sharp edge portion is the forming axis. The apron 51a has been adjusted so that its working surface is spaced from the forming axis a distance approximately equal to the thickness of the plate 298. The apron 51 has been adjusted so that its working surface is spaced from the forming axis a distance approximately equal to the thickness of both the plate 298 and the ply 299. It will be'seen that it is only because of such differential adjustment of the aprons that such a product can be produced.

In FIGS. 24 and 25 is illustrated the production of a sheet metal plate 300 having curved portions 301 and 302 of different radii from a common axis and having an offset nose or radial separating portion 303. In this case the mandrel 281, as previously described, has two coaxial semi-cylindrical portions 282 and 283 of correspondingly different radial size and the aprons 51, 51a have their working surfaces offset to correspond to the different radial sizes of these cylindrical portions. Accordingly, as the mandrels are swung about this common or forming axis the workpiece 300 illustrated in FIG. 25 is produced.

FIGS. 26 and 27 illustrate the production of a form from a workpiece 305 having a thick portion 306 and a thin portion 308 and with a step 309 therebetween which is assumed to be desired at the center of a bend. The forming axis is the axis of the cylindrical part 285 of the mandrel 284 and the working surfaces of the aprons 51, 51a are differentially adjusted from the forming axis to sweep around or stroke the surfaces of the thick and thin portions of the plate as shown in FIG. 27 to produce the 180 bend.

From the foregoing it wiil be seen that the differential adjustment provided for setting the working surfaces of the aprons 51, 51a at different distances from the working axis permits of producing forms, as illustrated in FIGS. 22-27, which otherwise could not be produced; the hydraulic cylinders 169, 169a are so connected to the frame and aprons 51, 51a as to have a very limited swing and not constitute an operational hazard; a unique adjustment, the driving section of which is mounted on the frame and the driven sections on the aprons 51, 51a is provided for adjusting the working surfaces of these aprons with reference to the working axis, and by the simple expedient of having worm wheels of one section releasing from worms of the other section on swinging either apron out, the above differential adjustment of the aprons is obtained; a simple adjustment is provided for the clamping ram 53 to bring the working axis of the mandrel 120 into concentricity with the main pivot pins 49, and a unique spring backed stop is provided for positioning the workpiece and at the same time compensating for the stretch of the metal. The aprons are furthermore swingably supported on the two large main pivot pins 49 through the large knuckles 142 which fully embrace these main pivot pins. Other features, such as the simple automatic apron return comprising the wires 191 winding on peripheral surfaces of the aprons 51, 51a and carrying the adjustable sleeves 198 and their stops or cams 209 for actuating the apron return switches 210, 210a will also be noted.

What is claimed is:

1. In' a brake for forming metal plate and sheet workpieces having a frame, a pair of forming aprons arranged in face-to-face relation on opposite sides'of a plane which includes the forming ms about which the workpiece is to be deformed and said aprons including working surfaces parallel and adjacent said forming axis, a clamping ram movable onsaid frame along said plane toward and from said working surfaces in opposed relation thereto, a mandrel carried by said clamping ram and having an exterior forming portion arranged to be brought into concentric relation with said forming axis by the movement of said clamping ram, and supporting pivot means on'said frame concentric with said forming axis at opposite ends of said aprons, thecombination therewith of an adjustable mounting for said aprons, comprising means pivotally supporting each apron on said supporting pivot means for independent adjustment of each of said Working surfaces relative to said forming axis and relative to each other whereby a workpiece can be produced having surfaces contacted by said working surfaces at different distances fromsaid forming axis.

2. In a brake for forming metal plate and sheet workpieces having a frame, a pair of forming aprons arranged in face-to-face relation on opposite sides of a plane which includes the forming axis about which the workpiece is'tobe deformed and said aprons including working surfaces parallel and adjacent said forming axis, a clamping ram movable on said frame along said plane toward and from: said working surfaces in opposed relation thereto, a mandrel carried by said clamping ram and having an exterior forming portion arranged to be brought into concentric relation with said forming axis by the movement of said clamping ram, and supporting pivot means on said frame concentric with said forming axis at opposite ends of said aprons, the combination therewithof an adjustable mounting for said aprons, comprising an adjusting mechanism mounted on said frame in said plane and including mov able driving means adapted to be releasably contacted from the exterior,.means on said frame for actuating said movable driving means, movable driven means mounted on each apron for movement into and out of engagement with said movable driving means to be driven thereby, supported pivot means for each apron pivotally supported on said supporting pivot means, and extensible adjusting means'on each apron operatively'interposed between its supported pivot means and its movable driven means and: moving its working surface toward and from said forming axis in response to movement of said movable driven means.

3. In a brake for forming metal plate and sheet work pieces having a frame, a pair of forming aprons arranged in face-to=face relation on opposite sides o'f a plane which includes the forming axis about which the workpiece is to be deformed and said aprons including working surfaces parallel and adjacent said forming axis, a clamping ram movable on said frame along said plane-toward and from said working surfaces in opposed relation thereto, amandrel carriedby said clamping ram and having an exterior forming portion arranged to be brought into concentric relation with said forming axisby the movement of said clamping'ram, and supporting pivot means on said frame worm fast to said adjusting shaft, means on said frame for selectively turning said adjusting shaft, supported pivot means for each apron pivotally supported on said supporting pivot means, at least one worm wheel on each apron releasabliy engaging said worm in the face=t'o-face position of said aprons, and extensible adjusting means on each apron operatively interposed between itssupported pivot means and its movable driven means and'moving its working surface toward and from said'forming axis inresponse to movement of said worm wheel.

i 4. In a brake for forming metal plate and sheet workpieces having a frame, a pair offorming aprons arranged in face-to-face relation on opposite sides of a plane which includes the forming axis about which the workpiece is to be deformed-and said'apro'ns including working surfaces parallel and adjacent said forming axis, a clamping ram movable on said frame along said plane toward and from said working surfaces in opposed relation thereto, a mandrel carried by said clamping ram and having an exterior forming portion arranged to be brought into concentric relation with said forming axis by the movement of said clamping ram, and supporting pivot means on said frame concentric with said forming axis at opposite ends of said aprons, the combination therewith of an adjustable mounting for said' aprons, comprising means pivotallysupportin'g' movable on said frame along said plane toward and from" said working surfaces in opposed relation thereto, a' man drel carried by said clamping ram and having anexterior forming portion arranged to be brought into concentric relation with said forming axis by the movement of said clamping ram, and pivot pins on said frame concentric with said forming axis at opposite ends of said aprons, the

combination therewith of an adjustablemounting for said aprons, comprising knuckles at opposite ends of eachapron pivotally embracing said pivot pins, extensible ad justable means operatively supporting each apron from its knuckle, and means actuating said extensible adjusting means.

6. A brake asset forth in claim 5 wherein said means for actuating said extensible adjusting means are mounted directly on said frame.

7. In a brake for forming metal plate and sheet workpieces having a frame, a pair of formingaprons arranged in face-to-face relation on opposite sides of a plane which includes the forming axis about which the workpiece is to be deformed and said aprons including working surfaces parallel and adjacent said forming axis, a clamping ram movable on said frame along said plane toward and from said workingsurfaces in opposed relation thereto, and a mandrel carried by said clamping ram and having an exterior forming portion arranged to be brought into concentric relation with said forming axis by the movement of said clamping ram, the combination therewith of an adjustable mounting for said aprons, comprising pivot pins on said frame concentric with said forming axis at opposite ends of said aprons, knuckles at opposite ends of each apron pivotally embracing said pivot pins, an interfitted screw member and nut member connecting each knuckle to the corresponding apron on an axis in a plane generally perpendicular to said forming axis, means holding one of said members against turning, means providing rotation of one of said members but preventing axial movement thereof, and means adjustably turning said last mentioned member.

8. A brake as set forth in claim 7 wherein an annular calibrated scale is provided around each of said last mentioned members to permit fine adjustment of said aprons to a predetermined position.

9. In a brake for forming metal plate and sheet Workpieces having a frame having end columns, a pair of forming aprons arranged between said columns in face-to-face relation on opposite sides of a plane extending longitudinally of said columns and which also includes the forming axis about which the workpiece is to be deformed and said aprons including working surfaces parallel with and adjacent said forming axis, a clamping ram slidably guided by said columns to move along said plane toward and from said working surfaces in opposed relation thereto, a mandrel carried by said clamping ram and having an exterior forming portion arranged to be brought into concentric relation with said forming axis by the movement of said clamping ram, supporting pivot means on said frame concentric with said forming axis at opposite ends of said aprons, and means pivotally supporting each apron on said supporting pivot means for swinging movement about said forming axis, the combination therewith of means for effecting such movement of each apron, comprising an extensible piston and cylinder at each end of each apron, and extending lengthwise of the corresponding end column means pivotally securing one end of each piston and cylinder to the outer end of the corres onding apron, means pivotally securing the other end of each piston and cylinder to the end of the corresponding column toward which said clamping ram moves in releasing the workpiece from said aprons, and means for introducing fluid under pressure to said cylinders and withdrawing fluid therefrom, said pistons and cylinders being substantially parallel with said columns in the face-to-face position of said aprons.

10. A brake as set forth in claim 9 wherein said means pivotally securing each piston and cylinder to the corresponding apron includes a bracket projecting horizontally outwardly from said apron in a direction generally perpendicular to and away from said plane.

11. In a brake for forming metal plate and sheet Workpieces having a frame, a pair of forming aprons arranged in face-to-face relation on opposite sides of a plane which includes the forming axis about which the workpiece is to be deformed and said aprons including working surfaces parallel and adjacent said forming axis, a clamping ram movable on said frame along said plane toward and from said working surfaces in opposed relation thereto, and a mandrel carried by said clamping ram and having an ex terior forming portion arranged to be brought into concentric relation with said forming axis by the movement of said clamping ram, the combination therewith of means supporting and actuating said aprons, comprising pivot'pins on said frame concentric with said forming axis at opposite ends of said aprons, knuckles at opposite ends of each apron pivotally embracing said pivot pins, a screw rotatably secured to each knuckle on an axis arranged in a plane generally perpendicular to said forming axis and held against axial movement relative to said knuckle, a nut fitting each screw and fixed to'the adjacent end of the corresponding apron, adjustment means turning said screws, and means for swinging said aprons around said forming axis, comprising an extensible piston and cylinder at each end of each apron and extending lengthwise of said plane, means pivotally securing one end of each piston and cylinder to the nut of the corresponding apron, means pivotally securing the other end of each piston and cylinder to the end of the part of the frame toward which said clamping ram moves in releasing the workpiece from said aprons, and means for introducing fluid under pressure to said cylinders and Withdrawing fluid therefrom, said pistons and cylinders being substantially parallel with said plane.

12. In a brake for forming metal plate and sheet workpieces having a frame having end columns, a pair of forming aprons arranged between said columns in faceto-face relation on opposite sides of a plane extending longitudinally of said columns and which also includes the forming axis about which the workpiece is to be deformed and said aprons including working surfaces paral. lel with and adjacent said forming axis, a clamping ram slidably guided by said columns to move along said plan toward and from said working surfaces in opposed relation thereto, a mandrel carried by said clamping ram and having an exterior forming portion arranged to be -brought into concentric relation with said forming axis by the movement of said clamping ram, supporting pivot means on said frame concentric with said forming axis at opposite ends of said aprons, and means pivotally supporting each apron on said supporting pivot means for swinging movement about said forming axis, means for effecting such movement of each apron, the combination therewith of means for reciprocating said clamping ram to different positions with reference to said axis, comprising a transverse pivot pin guided in longitudinal slots provided in each column, a bell crank lever pivoted at its center to swing about each pivot pin and having one arm projecting transversely with reference to said column and its other arm projecting lengthwise of said column toward said clamping ram, a link arranged lengthwise of each column and connecting said other arm of said bell crank lever with the corresponding end of said clamping ram and forming with said other arm of said bellcrank lever a toggle linkage, means for simultaneously swinging said one ends of said bell crank levers lengthwise of said columns, and means adjustably positioning each pivot pm at diflerent positions lengthwise of its column, comprising a coupled screw member and nut member arranged axially lengthwise of each column, means non-rotatably securing one of said members to said pin, means rotatably securing the other of said members to said column but holding the same against axial movement, and means for adjustably rotating both of said other of said members in unison.

13. A brake as set forth in claim 12 wherein said means for adjustably rotating said other of said members in unison comprises a worm wheel fixed coaxially to each of said other of said members, a worm engaging each worm wheel, coaxial adjusting shaft means journalled on said frame and connecting said worms, and means for adjustably turning said adjusting shaft means.

14. A brake as set forth'in claim 13 additionally including a manually releasable coupling in said adjusting shaft means between said worms whereby upon release of said coupling one of said pivot pins can the adjusted independably of the other pivot pin.

15. In a 'brake for forming metal plate and sheet workpieces having a frame, a pair of forming aprons arranged in face-to-face relation on opposite sides of a plane which includes the forming axis about which the workpiece is to be deformed and said aprons including working surfaces parallel and adjacent said forming axis, a clamping ram movable on said frame along said plane toward and I from said working surfaces in opposed relation thereto, a mandrel carried by said clamping ram and having an exterior forming portion arranged to be brought into concentric relation with said forming axis by the movement of said clamping ram, supporting pivot means on said frame concentric with said forming axis at opposite ends of said aprons, and means pivotally supporting each apron on said supporting pivot means, the combination therewith of power means for swinging said aprons about said supporting pivot means to bend opposite sides of the workpiece clamped against said aprons by said mandrel, and adjustable stop means stopping the swinging movement of each apron and reversing the action of said power means to return said aprons to said face-to-face position.

16. A brake as set forth in claim 15 wherein said adjustable stop means comprises a wire secured to a peripheral surface of each apron to be wound up thereon in response to the swinging of said apron, and a stop adjustably positionable along each wire, each of said stops so stopping the swinging movement of each apron and re- 18 versing the action of said power means to return said aprons to said face-to-face position.

17. A brake as set forth in claim 15 wherein said adjustable stop means comprises a wire secured to a peripheral surface of each apron to be wound up thereon in response to the swinging of said apron, a rod suspended from the free end of each wire, a tube surrounding each rod and adjustably positionable lengthwise thereof, and a stop projecting from each tube, each of said stops so stopping the swinging movement of each apron and reversing the action of said power means to return said aprons to said face-to-face position.

References Cited in the file of this patent UNITED STATES PATENTS 1,283,808 Krump Nov. 5, 1918 2,208,061 Warger July 16, 1940 2,501,241 Shaw Mar. 21, 1950 2,651,349 Smith Sept. 8, 1953 2,716,436 Cady Aug. 30, 1955 

